Over the last 4 weeks, I've test fired and mounted scopes on 4 different AR uppers/rifles- one Olympic, one CMMG, and 2 DelTon(one each M-4 and Hbar profile) . The lowers included Plum Crazy(carbon fiber factory assembled), Delaware Machine(assembled by myself), and a Sharps Rifle Company(also home built).
I can honestly say I'd put any of these up against any production built AR on the market. When 16" carbines are turning out 3/4" groups with low power optics, there's not much you can fault.There are good AR's from so many makers that it's a challenge to find a really bad rifle.